An intelligent assembly system was designed, which was used machine vision to identify the position, angle and type of the workpiece; the workpiece information was transmitted to the S7-1200 PLC controller through the Modbus-TCP communication protocol; the controller transmitted the workpiece data information to the controller of the multijoint robot according to the established program algorithm, furthermore, the robot could grasp and assemble the workpiece according to the pretaught program and algorithm. The system has high efficiency and good stability in practical application. By using the system, the manual cost can be effectively reduced, the control strategy can be flexibly changed according to different workpiece, which can bring great economic and social benefits.